我在foreach
循環中生成單選按鈕。我試圖將checked屬性綁定到父級中的基本可觀察元素。不幸的是,當點擊單選按鈕時,父級的屬性似乎沒有在點擊處理程序中更新。
基於一些previous work,似乎點擊處理程序應該是一個可以接受的位置來獲取視圖模型上的更新值。最奇怪的是,似乎在單擊單選按鈕幾次後,正確的值就會出現。
代碼:
function Question() {
this.name = "My Question";
this.answers = ko.observableArray([
new Answer(1, "Answer 1", false),
new Answer(2, "Answer 2", true),
new Answer(3, "Answer 3", false)]);
this.correctAnswer = ko.observable(2);
}
function Answer(id, name, isRight) {
this.id = ko.observable(id);
this.name = ko.observable(name);
this.isRight = ko.observable(isRight);
}
ko.applyBindings(new Question());
$(document).on("click", "input[type='radio']", function() {
var answer = ko.dataFor(this);
var question = ko.contextFor(this).$parent;
var answerId = answer.id();
var correctAnswer = question.correctAnswer();
alert(answerId + " should equal " + correctAnswer +
(answerId === correctAnswer ? " SWEET" : " DAMNIT"));
});
HTML
<div data-bind="text:name"></div>
<div data-bind="foreach:answers">
<label>
<span data-bind="text: name"></span>
<input type="radio" name="X" data-bind="value: id, checked:$parent.correctAnswer" />
</label>
<br />
</div>